Got Any Milk to Preserve? Now you surely can ! Researchers Find A Way To Extend Milk’s Shelf Life
You no longer have to fear your housemate’s penchant for keeping ten-day old milk hanging around the apartment!
Researchers at Purdue University and the University of Tennessee are helping avert the traumatic starts to our morning with a new, non-chemical treatment that promises to extend regular milk’s shelf life to around 2-3 weeks that too, without affecting the nutrients or flavor.
Refrigerated pasteurized milk typically lasts about two to three weeks before turning into a wretched hive of scum and villainy. Researchers have shown that the shelf life of milk can be extended by several weeks by rapidly heating and cooling it.
By increasing the milk’s temperature by 10 degrees Celsius for just one second, they have added seven more weeks to the usual lifespan of refrigerated milk.
Bruce Applegate, associate professor in the Department of Food Science at Purdue, said: “It’s an add-on to pasteurization, but it can add shelf life of up to five, six or seven weeks to cold milk.”
Pasteurization, which removes significant amounts of harmful pathogens that can cause illness and eventually spoil dairy products, is
considered a high-temperature, short-time method. Developed by Louis Pasteur in the 19th century, the treatment gives milk a shelf life of about 2-3 weeks.In the study, the low-temperature, short-time (LTST) method sprayed tiny droplets of pasteurized milk, which was inoculated with Lactobacillus and Pseudomonas bacteria, through a heated, pressurized chamber, rapidly raising and lowering their temperatures about 10°C but still below the 70°C threshold needed for pasteurization. The treatment lowered bacterial levels below detection limits and extended shelf life to up to 63 days.
“With the treatment, you’re taking out almost everything,” Applegate said. “Whatever does survive is at such a low level that it takes much longer for it to multiply to a point at which it damages the quality of the milk.”
Sensory tests compared pasteurized milk with milk that had been pasteurized and run through the LTST process. Panellists did not detect differences in color, aroma, taste or aftertaste between the products.
Phillip Myer, an assistant professor of animal science at the University of Tennessee and a co-author of the paper, published in the journal SpringerPlus, said the process uses the heat already necessary for pasteurization to rapidly heat milk droplets.
“The process significantly reduces the amount of bacteria present, and it doesn’t add any extra energy to the system,” Myer said. He said the promise of the technology is that it could reduce waste and allow milk to reach distant locations where transport times using only pasteurization would mean that milk would have a short shelf life upon arrival.
Applegate said the process could be tested without pasteurization to determine if it could stand alone as a treatment for eliminating harmful bacteria from milk.
So is this some fascinating research project which won’t hit shelves for the foreseeable future? Apparently not.
“Currently an Ohio-based milk processor is using this technology and distributing the milk,” Applegate says. “The unit is approved for processing milk in Ohio and distribution nationwide. The product is currently being distributed, however it has not been labeled as extended shelf life milk. Once the commercial application is validated the milk will be labelled with the extended shelf life.”
